HOLOTRICHA 521 



cilia; dorsal surface with 3 rows of short bristles; cytostome sur- 

 rounded by a ring; cytopharynx with long trichocysts; posterior 

 end drawn out into a tail; contractile vacuoles, 2 or more; body 

 ciliation uniform; macronucleus bandform, moniliform or divided 

 into numerous independent bodies; fresh or salt water. Many 

 species. 



D. americanus Kahl (Fig. 239, h). Proboscis bent dorsally 

 sickle-like; macronucleus made up of 2 sausage-shaped or often 

 horseshoe-shaped parts; 2 contractile vacuoles on dorsal side; 

 200 iu long; in mosses. 



D. anser (Mtiller) (Figs. 22, c, d; 239, c). Proboscis slightly flat- 

 tened; macronucleus divided into numerous bodies; contractile 

 vacuoles in a row on dorsal side with 2-3 contractile vacuoles in 

 proboscis; 250-400^, sometimes up to OOO^t long; fresh water. 



Genus Paradileptus Wenrich {TentacuUfera Sokoloff). Body 

 broader at the level of cytostome; with a w4de peristomal field 

 which bears the cytostome and is surrounded for 2/3-3/4 its 

 circumference by a raised rim which is continuous anteriorly 

 with the spirally wound proboscis; trichocyst-zone traversing 

 rim and anterior edge of proboscis; contractile vacuoles small, 

 numerous, distributed; macronucleus segmented, fresh water. 



P. conicus W. (Fig. 239, d). 100-200^ by 50-100;u. 



P. rohustus W. (Fig. 239, e). 180-450^ long. 



Genus Branchioecetes Kahl. Preoral part somewhat like that 

 of Amphileptus, and bent dorsally; ventral side of neck with 2 

 rows of trichocysts; cytostome at posterior end of neck; cyto- 

 pharynx with trichocysts; ectocommensals on Asellus or Gam- 

 marus. 



B. gammari (Penard) (Fig. 239, /). 130-200^ long; on Gam- 

 marus. 



Family 3 Loxodidae Roux 



Genus Loxodes Ehrenberg. Lancet-like; strongly compressed; 

 anterior end curved ventrally, and usually pointed; right side 

 slightly convex; uniform ciliation on about 12 longitudinal rows; 

 ectoplasm appears brownish, because of closely arranged brown- 

 ish protrichocysts ; endoplasm reticulated; 2 or more vesicular 

 macronuclei; 1 or more micronuclei; 5-25 Miiller's vesicles (p. 77; 

 Fig. 30, a, 6) in dorsal region; fresh water. 



L. vorax Stokes (Fig. 239, g). 125-140^ long; yellowish brown, 

 a row of slightly longer cilia; sapropelic in standing fresh water. 



